Kinetics of simultaneous reactions between liquid iron-carbon alloys and slags containing MnO

The oxidation rates of carbon, phosphorus, and silicon; the desulfurization rate of liquid iron; and the simultaneous reduction rate of MnO from slag were examined at 1450 degrees C to 1550 degrees C by using high carbon iron alloys and CaO-SiO2-CaF2 slags containing MnO and FeO, The reaction rates were well reproduced by a kinetic model describing the reaction between the slag and multicomponent iron alloys. The controlling steps applied for the reactions considered in the present kinetic simulation were as follows. Th e rate of decarburization is controlled by the chemical reaction at the sla g-metal interface, and those of the other reactions are controlled by the t ransport in slag and metal phases. Both observation and simulation results showed that MnO was not a strong oxidizer compared with FeO in the slag, bu t was an effective component for desulfurization. The simulation results al so showed that the interfacial oxygen activity using MnO-based slag was muc h lower than that using FeO-based slag. The apparent equilibrium constants of phosphorus and sulfur, which were obtained by the kinetic modeling of-ex perimental results, were found to increase with increasing the (MnO + CaO)/ SiO2 ratio of the slag. The controlling step(s) of each element transport a cross the slag-metal interface was discussed with the aid of the kinetic mo del.